Tinea capitis (scalp ringworm) is a fungal dermatophyte infection of scalp hair follicles that afflicts 3-8% of the U.S. pediatric population. Tinea capitis is a major health care disparity because it occurs predominantly among individuals with a disadvantaged socioeconomic background and sub-Saharan African descent. Diagnosis of tinea capitis is currently dependent on culture and microscopy. Both are expensive, take time and require considerable expertise. The goal of this project is an immunoassay that will rapidly identify the presence of dermatophyte fungi in skin scrapings and hair. The target population will be individuals, primarily disadvantaged children, with a clinical presentation of tinea capitis. The approach will be an immunoassay for cell wall galactomannans as biomarkers for dermatophyte fungi. The product will be a rapid and inexpensive lateral flow immunoassay (LFIA). The LFIA platform is familiar to health care workers and patients alike because the format is identical to that of the home pregnancy test. As a consequence, there would be ready acceptance of the test by all stakeholders. In preliminary studies, a multi-step research-grade LFIA was produced that is reactive with galactomannans of all major dermatophytes as well as extracts of clinical samples from patients with dermatophyte infection. The objective of this Phase I proposal is to move the current research-grade LFIA to a format suitable for point-of- care (POC) use. This objective will be completed by pursuit of three specific aims. Aim 1 will optimize procedures for sample treatment and extraction of galactomannan from dermatophytes. Aim 2 will optimize a prototype lateral flow immunoassay for detection of galactomannan in a single-step POC format. Aim 3 will evaluate a prototype tinea capitis LFIA using clinical samples. If successful, this study will produce a diagnostic test that is efficient, effective, affordable, culturally acceptable, and deliverable to sites that serve health disparity populations. The result will be rapid diagnosis and treatment of an infection that stigmatizes children, keeps them from school until treatment is initiated, and adds a considerable cost to the health care system.